Web tensioning mechanism



Sept 19,1933. A J HoRToN WEB TENS IONING MECHANI'SM 5 sheets-Sheet 1Filed Nov. l2, 1931 INVENTOR Sept. 19, 1933. A. J. HoRToN 1,927,589

WEB TENS IONING MECHANI SM Filed Nov. 12, 1931 3 Sheets-Sheet 2 Sept.19, 1933. Al J, HQRTON 1,927,589

WEB TENS IONING MECHANISM Filed NOV. 12, 1931 5 Sheets-Sheet 5 gliPatented Sept. 19, 1933 UNITED STATES WEB TENSIONING MECHANISM Albert J.Horton, White'Plains, N. Y., assignor to Rnloe & Co., Inc., New York, N.Y., a corporation of New York; Irving Trust Company,

receivers Application November 12, 1931 Serial N0. 574,502

15 Claims.

This invention relates to certain improvements in web roll controllingmechanism, that is, tension devices for controlling the unwinding ofrolls of web material, and has been particularly designed for use incontrolling the unwinding of web rolls in printing machines. A

In feeding the web to the printing mechanism, it is desirable that theweb be found under such tension as to produce good printing, suchtension being called herein the normal running tension of the web. It isalso desirable that additional tension be applied to the web if a slackshould occur, due to a break in the web or a sudden stoppage of thepress to which the web is being fed. In a copending application of HarryV. Ball and Albert J. Horton, Serial No. 565,940, there is described animproved mechanism which functions to produce a suitable normal runningtension on the web and which will act to provide an additional orauxiliary tension, in case of a slack in the web, to quickly stop theweb roll and prevent overrunning of the web. l

Generally speaking, the construction shown in said application comprisesfriction belts or straps engaging the surface of the unwinding roll withmeans for exerting a normal running tension on these straps, a drop rollengaging the running web, and mechanism actuated by the downwardmovement of the drop roll for causing an increased pull on the straps soas to exert an increased tension on the roll, said construction alsoincluding friction bands acting to permit an overtravel of the drop rollso as to take up any slack that might be formed in the web in case theweb roll is not instantly stopped by the application of the additionalpressure on the straps.

The mechanisml shown in this copending application operates entirelysuccessfully for the purpose for which it has been designed, but suchmechanism has certain complications which it is desirable to avoid, andit is the especial object of the present invention to provide animproved mechanism of simpler form than that referred to in suchapplication which will function to 45 produce the desired normal runningtension on the web and which will provide the additional or auxiliarytension when required, and in which means are provided for permitting anovertravel of the controlling d rop roll so as to take up any slackwhich may be formed in the web in the event that the unwinding web rollis not quickly stopped by the tension devices or straps used for thispurpose.

With this and other objects not specifically referred to in View, theinvention consists in certain novel parts, arrangements and combinationswhich will be fully described in connection with the accompanyingdrawings and the novel features pointed out in the claims hereuntoannexed.

In these drawings, which show a preferred embodiment of the invention,-

Figure 1 is an end elevation, partly broken away and partly in section,embodying the improvements of the present invention;

Figurev 2 is a detail side'view of part of the 65 construction shown inFigure 1 on an enlarged scale, the View being partly broken away andpartly in section;

Figure 3 is a view similar to Figure 2 showing the parts in a differentposition;

Figure 4 is a top or plan view, partly'in section, of the constructionshown in Figure 2, the View being taken in the direction of arrow 4 ofthat ligure;

Figure 5 is a side view, partly in section, of a portion of theconstruction shown in Figure 1 looking in the direction of arrow 5 ofthat figure;

Figure 6 is a sectional view of the improved spring drum arrangement forapplying the additional tension to the straps or belts, the sectionbeing taken looking in the direction of arrow 6 of Figure 4, and

Figure '7 is a detail section view of an adjustable Weight which may beemployed to counter weight the controller drop roll, the view beingtaken in the direction of arrow 7 of Figure 4.

Referring now to these drawings, the various parts of the mechanism aremounted on suitable side frames, one of which is indicated at 1.

The particular mechanism selected to illustrate the invention includesmeans for supporting a running roll R and a spare roll indicated at S,these rolls being mounted so that they can be moved from loading torunning position. It will be understood, of course, that a single webroll may be used or any suitable mechanism may be employed forsupporting the running roll and one or more spare rol1s. As shown, therolls are supported in suitable chucks or bearings 2, 3 formed in theends of arms 4, one of which is 100 shown in Figure 1, mounted on ashaft 5 which can be driven in any suitable manner to move the rollsfrom loading to running position.

As in the copending application referred to, a tension mechanism isemployed which frictionally 105 engages the surface of the web roll overwhich the web is being led to the press, which exerts a normal runinngtension on the web roll to insure sufficient or suitable tension forgood printing. While the specific construction of these tension 110devices may be varied, as shown, such tension devices are in the form ofa plurality of belts or straps, two such straps 6, 7 being shown andarranged to have a substantial wrap or lap around the unwinding roll, asshown in Figure 1, the straps following the roll as it `decreases insize so that the requisite tension is kept thereon. These straps, attheir lower ends, are supported, by means of hooks 8, around a bar orrod 9 mounted in blocks 10 suitably supported on the floor of thepress-room or other suitable support.

Machines constructed in accordance with the invention will provide anormal or running tension onthe belts or straps and an increased tensionor pull on the straps in case of a slack or loose condition in the web,and a simple mechanism for accomplishing this has been provided by thepresent invention. While but two tension belts or straps 4areillustrated, it will be understood that in the best constructions foursuch straps will be provided. The mechanism shown in Figure 4v beingone-half of the machine and the other half being a duplicate of thatshown in Figure 4, it therefore need not be illustrated. With thisarrangement, when a full width roll is being used, four belts or strapswould be operating, a three-quarter roll would be operating with threestraps, and a half roll with two straps.

With the particular construction, illustrated there is provided amechanism for exerting a comparatively light or normal running tensionon the straps and means for providing an increased tension or pull onthe straps, two of these mechanisms being shown in. Figure 4, markedgenerally 11, 12, which will be more fully described hereinafter.

While the particular mechanism for controlling the pull or tension onthe straps may be somewhat varied, in that selected to illustrate theinvention a controller mechanism is shown which includesa member whichrests onta loop of the web, the tensioning mechanism being operated byan upward or downward movement of this controller member. This member isshown as a roll 13 journalled in the ends of a pair of arms 14,one ofwhich is shown in Figure 4, it being understood that this is duplicatedon the other side of the machine. These arms, at their other ends, arefast on a rock shaft 15 suitably supported in bracket arms 16 secured tothe side frames before referred to.

'I'he web marked W is led from the running roll under a guide roll 417over a tension roll 18, of usual construction, under the controller 13to the press. 'Ihe controller roll is held in the upper position, asshown in Figure 1, by the pull of the web going to the press, but if aslack occurs in the web, for any reason, rthis controller roll movesdownwardly, and this downward movement of the controller or drop rollputs into operation the mechanisms 12, whereby the increased tensionrequired is put on the center straps, as the straps 7. It will beunderstood that the normal tension of the straps keeps such a tension onthe web that the drop roll is held in its upper position by the webtension, but the roll is permitted to drop if there is a break in theweb or a slack condition from other causes.

This particular mechanism which is employed for operating the means forapplying increased tension to the center straps may be somewhat varied,but, as shown, this mechanism includes a controller arm 19 on therock-shaft 15, which has pivoted thereto one end of a link 20, and atits other end this link is pivoted to one end of a pawl arm 21 securedto what may be termed a drum-shaft 22 suitably supported in bearings 22on the bracket arm 16, before referred to. The link 20 carries a stop 23which engages the Atail 24 of a pawl 25 pivotedv at 26 on the pawl arm21, before referred to, this pawl being arranged to engage the teeth ofa ratchet 27 on the drum-shaft 22, before referred to.

This drum-shaft 22 supports drums 28, one of which is shown, whichtogether with certain mechanism is provided for exerting an increasedpull on certain of the straps, as, for instance, the two center straps7, one of which and its associated mechanism being shown in Figure 4,generally marked 12. This mechanism includes a double spring drumconstruction and includes a sleeve 30 secured to the shaft 22 and aspiralor clock spring 31, the inner end of which is secured to thesleeve and the outer end to a spring support or drum 32. This drum 32 isformed with a sleeve 33, to which the inner end of a spiral or clockspring 34 is secured, the outer end of this clock spring being fastenedin the wall of a drum 35, as indicated at 36 and best shown in Figure 6.This drum 35 is provided with a hub 37 and turns freely on the sleeve33.

The clock spring 34 is a relatively strong spring and,'during theoperation of the mechanism, is released to the limit permitted by thecapacity of the interior of the drum 35. The spring 31 and the spring 29are relatively weak, the spring 29 providing the normal running tensionto the to the belt 6, and the spring 31, to which the belt 7 is secured,acting to rotate the drumv 32 and keep the straps 7 in contact with theweb roll, ready for quick-'application of the heavy spring 34.-

' When, however, the drop roll 13 descends, through the connectionsheretofore described, the stop 23 is released from the pawl 25 andthepawl engagesv the teeth of the ratchet 27, and this movement acts toturn the shaft and with it the drum 32. This movement, through theconnection between the two drums, puts the tension on the comparativelyheavy spring 34, thereby increasing the pull on the tension strap, foras the' drum 32 is turned, through the action of the pawl, the spring 34is put under a tension which is communicated to the drum 35. It willthus be understood that under ordinary starting and vrunning conditionsa web roll is held under a running tension caused by the springs 31 and29. Under certain' conditions, however, such as a break in the web orother slack condition, the tension or pull on the straps is increasedthrough the relatively heavy spring 34.

In the best constructions, means arc provided for adjusting theeffective weight of the drop roll 13 and, as illustrated, these meansconsist of a weight 38, which is slidable on a bar 39 supported in abracket 40 securcdto the rock-shaft 15, before referred to. The positionof this weight or arm 39 can be adjusted to counterweight the roll 13,and it will be understood that the tension exerted by the springmechanism described and the counterweighting of the drop roll is'soproportioned that, after the pawl and ratchet mechanism and the spring34 have acted to put the increased tension or pull on the straps, anovertravel of the roll is permitted, so as to take up any excessweb'which may have run from the roll, the spring connections permittingthe drop roll to extend through a considerable travel,

consequently allowing a longer period of time in which to stop the webroll.

a In the best constructions, means will be provided for quicklytensioning the relatively heavy spring 34, so that the additionaltension or pull will be applied to the straps very quickly and willrequire but a small descent of the drop roll from the position shown inFigure 1 toward that shown in Figure 3. In the particular constructionillustrated, there is provided a supplementary spring, marked 41, bestshown in Figure 6, which4 is located inside the spring 34 and-secured tothe sleeve 33, before referred to, the two springs being held inposition, as shown in Figure 6, by set screws 42. With thisconstruction, the initial tension of the spring 34 is provided veryquickly, so that the drop roll 13 only has to travel approximately onequarter of its way down to exert the required heavy tension on thestraps, the balance of its travel being available to take care of excessweb that may be caused by the tendency of the web roll to run ahead.

It will be understood, as before stated, that the tension of the webacts to keep the drop roll 13 in its upper position, or that shown inFigure 1. To limit this movement, there is preferably provided aresilient stop device, shown in Figure 5 as comprising flat springs 43and a stop 44, and the lower travel of the roll is or may be defined bya stop pin 45, see Figure 4, with which the roll arm 14 engages andstops the downward movement of the roll.

It will further be observed that the roll support which supports themain roll and the spare roll can be rotated at any desired ti'me. Whenthe drop roll 13 is in the upper position shown in Figure 1, the pawl 25is disengaged and the drums 32, 35 are free to rotate, so that thestraps may be paid out or wound up as required but held only against thetension of the light springs 29, 31. If, however, the drop roll is inits down position, as shown, for instance in Figure 3, and the pawl isstill in engagement with the ratchet 27, the support may still berotated even against the action of the relatively heavy spring 34.However, if the press be started when such heavy tension is on, the pullor tension on the web will at once raise the roll 13 and remove thetension from the heavy spring 34.

It will be seen withthe construction shown and described that a verysimple and efficient mechanism has been provided for applying a normalrunning tension on the roll controlling straps, for providing theincreased tension needed in case of a break in the web or other slackcondition, and permitting overtravel of the drop roll to take up anyexcess slack of the web due to overrun, such mechanism operatingautomatically and requiring practically no adjustment.

While the invention has been shown and described in its preferred form,it will be understood that certain changes and variations may be made inthe specific structure provided for carrying out the invention without,however, departing from the spirit of the invention as defined in theappended claims.

What is claimed is:

l. Web tensioning mechanism including in combination friction strapsengaging the surface of the unwinding web roll, spring means connectedwith the straps for exerting a normal running tension on the straps, amovable controller roll engaging the web, spring means for exerting anincreased pull on a strap to increase the tension on the roll, andconnections actuated by the movement of the controller roll foractuating the latter spring means.

2. Web tensioning mechanism including in combination friction strapsengaging the surface of an unwinding web roll, spring means connectedwith the straps for exerting a normal running tension on the straps, adrop roll engaging the web, spring means for exerting an increased pullon a strap, and connections actuated by the downward movement of thedrop roll for actuating the latter spring means.

3. Web tensioning mechanism including in combination friction strapsengaging the surface of an unwinding web roll, means connected with thestraps and exerting a normal running tension on the straps, a drop rollengaging the web, spring means for exerting an increased pull on astrap',

and connections actuated by the downward move- 1 ment of the drop rollfor actuating the spring means. l

4. Web tensioning mechanism including in combination friction strapsengaging the surface of an unwinding web roll, means connected with thestraps and exerting a normal running tension thereon, a drop rollengaging the web, a shaft rocked by the downward movement of the roll,av

6. Web tensioning mechanism including inY combination friction strapsengaging the surface of' an unwinding web roll, a spring havingconnection with one of the straps, a spring having connection withanother of said straps, a heavier spring connected to the latter of saidstraps, a booster spring connected with the heavy spring, and means foractuating the heavy spring to put a tension on the strap connectedthereto greater than the tension exerted by the lighter spring.

7. rllensioning mechanism for unwinding web rolls, including incombination straps engaging the roll surface, a comparatively lightspring connected with one of the straps, a spring mechanism connectedwith another of the straps and comprising a light spring normally activeand a heavier spring normally having minimum tension, and means forincreasing tension on the heavy spring to put a tension on the strapgreater than the tension exerted by the light spring.

8. Tensioning mechanism for unwinding web rolls, including incombination straps engaging the roll surface, a comparatively lightspring connected with one of the straps, a spring mechanism connectedwith another of the straps and comprising a light spring normally activeand a heavier spring normally having minimum tension, means forincreasing tension on the heavy spring, and a booster spring connectedwith the heavy spring for accelerating the tensioning thereof.

9. Tensioning mechanism for unwinding web rolls, including incombination straps engaging the roll surface, a shaft, a spring drum onthe shaft to which one of the straps is connected, 'a double spring drummechanism on the shaft including light and heavy springs, the heavyspring normally having minimum tension and being connected to anotherstrap, a drop 1011 engaging the web, and pawl and ratchet connectionsactuated by the downward movement of the drop roll for turning the drumof the heavy spring to increase tension on it.

10. Web tensioning mechanism including in combination, a friction strapengaging the surface of an unwinding web roll, a spring means connectedwith the strap for exerting a normal running pull thereon, a movablecontroller roll engaging the web, a second spring means connected withthe strap for exerting an increased pull, and a connection whereby thesecond spring means is tensioned by movement of the controller roll; theinitial movement of the controller roll acting to exert an increasedpull on the strap and further movement of the controller roll beingpermitted, to maintain tension on the web.

11. Tensioning mechanism for unwinding web rolls including incombination, a shaft, a collar secured to the shaft, a rst drumrotatable on the shaft, a first spring connecting the collar to thedrum, a second drum, a second spring connectingthe first drum to thesecond drum. a strap connected to the second drum and adapted to pressagainst the surface of the web roll, and means for increasing .tensionon one of the springs to increase the pressure of the strap.

12. Tensioning mechanism for unwinding web rolls including incombination, a shaft, a collar secured to the shaft, a first drumrotatable on the shaft, a first spring connecting the collar to thedrum, a second drum, a second spring connecting the first drum to thesecond drum, a strap connected to the second drum and adapted to pressagainst the surface of the web roll, a drop roll engaging the web, andconnections from the drop roll for increasing tension on the secondspring to increase the pressure on the strap.

' 13. In a mechanism for maintaining tension on a web drawn from a, webroll, a drop roll held in movable roll supports and engaging the web, astrap held under tension and arranged to press against the roll, aspring support, a first spring connecting the strap to the springsupport, 4a second spring connecting the spring support to an anchorage,and means connected to the movable roll supports to move the springsupport when the Web slackens and thereby increases the tension on thestrap.

14. In a. mechanism for maintaining tension on a web drawn from a webroll, a drop roll in running engagement with the web, a strap held undertension and arranged to press against the roll, a spring support, aheavier spring connecting the strap to the spring support, a lighterspring connecting the spring support to a fixed member, and meansoperable by a motion of the drop roll transversely to its axis, wherebythe spring support is moved to increase tension on the heavier springand the rotation of the web roll is checked when the web slackens.

15. In a mechanism for maintaining tension on a web drawn from a webroll, a drop roll in running engagement with the web and supported tomove transversely to its axis when the web slackens. a shaft, a springsupport rotatable on the shaft, a drum rotatable on the shaft, a springconnection between the shaft and the spring support, a spring connectionbetween the spring support and the drum, a strap bearing againstthe rolland having one end secured to the drum and the other end secured to afixed member, and means operable by motion of the drop roll transverselyto its axis whereby the drum is rotated to tighten the strap when theweb slackens.

' ALBERT J. HORTON.

